Printing Wastewater Treatment And Reuse Of Reclaimed Water

Since the 1980s,the printing and dyeing industry has sprung up.Printing in the printing process refers to the formation of a pattern on the fabric,specifically printing a dye or paint onto the fabric,which may also be referred to as partial dyeing of the fabric.The printing industry is an industry with a large amount of water and a large amount of waste water.Generally speaking,the concentration of pollutants in printing wastewater is higher than that of dyeing wastewater.Taking this problem into consideration,comprehensive treatment of wastewater and subsequent discharge can not only reduce environmental pollution,but also reduce the expenditure of printing enterprises on water fees,bringing economic benefits to enterprises.With the reduction of pollutant concentration limits in emission standards and the continuous increase of water and sewage charges,printing enterprises have paid a high degree of attention to clean production,and the reuse of printing wastewater has gradually attracted people's attention.Especially in recent years,scholars and environmental protection personnel have done a lot of research and exploration on the reuse of printing wastewater.The results show that the printing wastewater can be reused after the process,and it is economically feasible.The printing enterprises in Guangdong are widely dispersed,the amount of wastewater is large,the discharge of wastewater is difficult to control,and centralized treatment is difficult to achieve,and the amount of wastewater is generally large.At the same time,the printing wastewater has the characteristics of high dye additive,complex pollutants and poor biodegradability,which makes the printing wastewater difficult to handle.In order to achieve the maximum emission reduction of printing and dyeing wastewater and water conservation,it is urgent to regenerate and reuse the recycled water after printing wastewater treatment.In view of the characteristics of printing wastewater in Guangdong,this paper adopts the combination process of“coagulation air flotation-acidification hydrolysis-anoxic-contact oxidation-precipitation”as a primary treatment system to remove pollutants from printing wastewater,and achieve wastewater discharge standards.On this basis,coupled with the advanced treatment process of secondary artificial humidity,the engineering design of water reuse in printing wastewater was carried out,and the stability and feasibility of the engineering system were analyzed through continuous operation to minimize the discharge of enterprise wastewater and realize the enterprise.Sustainable development.The main research contents of this thesis are:The first chapter summarizes the printing and dyeing industry and wastewater discharge status related to this paper.In addition,the research progress of printing wastewater treatment technology is summarized,and the necessity of this paper is put forward.Chapter two:through the field investigation and data analysis,summarizes the process overview of a printing enterprise,and analyzes the water consumption and wastewater generation,providing a basis for the subsequent selection process.The third chapter introduces and compares several process principles and processes for treating printing wastewater.According to the actual situation of the printing enterprise,the printing wastewater treatment plan was determined,and the printing wastewater was selected by the first-stage treatment process of“coagulation air flotation”,“acidification hydrolysis”,“hypoxia”and“contact oxidation”and“precipitation”.On the basis of this treatment,coupled with the secondary artificial humidity deep treatment process,making full use of the characteristics of the stable operation of the constructed wetland process,using the low load and long residence time operation mode,further reducing the COD and ammonia nitrogen of the water,ensuring the return The water quality meets the printing production process requirements,and the integrated engineering design of printing wastewater treatment and reclaimed water reuse is carried out.Chapter four:the pilot operation of the integrated wastewater treatment project,the first-stage treatment process to achieve the water quality index of the water reuse of the Guangdong Province landmark first-class discharge standard,and then the combined treatment of the constructed wetland.The results of the pilot test show that the primary treatment process effluent reaches the first-level emission standard of Guangdong Province,and the water reuse index of the effluent after the advanced treatment of the constructed wetland is combined.The maximum water reuse rate is 25%.Chapter five:Continuously commissioning and running the secondary and secondary treatment and reuse projects of printing and dyeing wastewater with 25%water reuse rate.After the stable operation of the wastewater treatment system,the effluent from each section of the original wastewater was monitored,and the COD,pH,color,total solids content and conductivity were monitored,and the operation and treatment effects of the treatment and reuse project were further examined.The feasibility of recycling.From the monitoring results,the average COD of raw water is about 500mg/L,and the average COD of wetland treated effluent is about 50mg/L.The calculated COD removal rate is about 90%or more;the original wastewater is acidic,and the system is passed through the system.After treatment,the pH of the effluent is neutral as a whole;the chromaticity is reduced from the original 700¹000mg/L to below 60mg/L after the first-stage system treatment,and then the effluent color is maintained below 18 after the second-stage wetland treatment;After the treatment and reuse of the treatment,the TDS monitoring value of the recycled water is stable at 60 mg/L.In terms of electrical conductivity,the conductivity of the effluent after the advanced treatment of the secondary wetland shows very good stability and is stable at 125 S/m.According to statistics,there were 20,000 to30,000 tons of recycled water in 2014 and 2015.In 2016,there were about 90,000 tons of recycled water,and the recycling rate reached about 29%,achieving the goal of reducing emissions.Chapter six:Through the calculation and using this process to treat the printing wastewater of the plant,the company has achieved good results in saving water resources.The discharge of wastewater has changed from 360,000 t/a to 25.2.t/a,a decrease of 30%.The annual income can be 459,000 yuan,the total amount of COD_Cr emission reduction is6.09t/year,and the total amount of ammonia reduction by emission is 0.812t/year.